Mitosis Homework/AP Biology
Please use your own lined paper to complete the following assignment
This activity will count as two homework assignment grades.
1. How can there be 46 chromosomes in a human cell at metaphase and also 46 chromosomes
in each daughter cell?
2. Describe the events in each of the following phases of the cell cycle; G1, S, G2, and M.
3. Briefly describe how prokaryote chromosomes differ from those of eukaryotes.
4. Explain the difference between a chromatid and a chromosome, using a diagram with
5-6. List the stages of mitosis in proper order. Diagram the stages and give the major events in
7. How does cytokinesis differ in plants and animals.
8. How does mitosis ensure that each daughter cell has the same genetic makeup as the parent cell?
9. List and briefly discuss at least two factors that control and regulate cell division.
Use the information provided below and your knowledge of biology to answer questions 10 through 12
When a population of cells is examined with a microscope, the percentage of cells in the M phase is
called the mitotic index. The greater the proportion of cells that are dividing, the higher the mitotic
index. In a particular study, the cells from a tissue culture are spread on a slide, preserved and stained,
and then inspected with a microscope. A hundred cells are examined: 9 cells are in prophase; 5 cells are
in metaphase; 2 are in anaphase; 4 cells are in telophase; the remainder, 80 cells, are in interphase.
10 What is the mitotic index for this cell culture? (the mitotic index is the time of the M phase divided
by the entire length of the cell cycle)
11. The average duration for the cell cycle in this culture is known to be 20 hours. What is the
duration of interphase? Of metaphase?
12. Going back to the living culture of these cells, the average quantity of DNA per cell is measured.
Of the cells in interphase, 50% contain 10 ng (1 nanogram = 10 -9 gram) of DNA per cell,
20% contain 20 ng of DNA per cell, and the remaining 30% of the interphase cells contain
amounts of DNA between 10 ng and 20 ng. Based on this data, determine the duration of the G1,
S, and G2 portions of the cell cycle.